Carry the triggered rule in subclasses of BlockException (#469)

* Extract getRule in BlockException and refine override methods in subclasses

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/BlockException.java

@@ -15,8 +15,9 @@
  */
 package com.alibaba.csp.sentinel.slots.block;
 
-/***
- * Abstract exception indicating blocked by Sentinel due to flow control, degraded or system guard.
+/**
+ * Abstract exception indicating blocked by Sentinel due to flow control,
+ * circuit breaking or system protection triggered.
  *
  * @author youji.zj
  */
@@ -42,6 +43,7 @@ public abstract class BlockException extends Exception {
         THROW_OUT_EXCEPTION.setStackTrace(sentinelStackTrace);
     }
 
+    protected AbstractRule rule;
     private String ruleLimitApp;
 
     public BlockException(String ruleLimitApp) {
@@ -49,6 +51,12 @@ public abstract class BlockException extends Exception {
         this.ruleLimitApp = ruleLimitApp;
     }
 
+    public BlockException(String ruleLimitApp, AbstractRule rule) {
+        super();
+        this.ruleLimitApp = ruleLimitApp;
+        this.rule = rule;
+    }
+
     public BlockException(String message, Throwable cause) {
         super(message, cause);
     }
@@ -58,6 +66,12 @@ public abstract class BlockException extends Exception {
         this.ruleLimitApp = ruleLimitApp;
     }
 
+    public BlockException(String ruleLimitApp, String message, AbstractRule rule) {
+        super(message);
+        this.ruleLimitApp = ruleLimitApp;
+        this.rule = rule;
+    }
+
     @Override
     public Throwable fillInStackTrace() {
         return this;
@@ -98,4 +112,8 @@ public abstract class BlockException extends Exception {
 
         return false;
     }
+
+    public AbstractRule getRule() {
+        return rule;
+    }
 }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/authority/AuthorityException.java

@@ -17,9 +17,11 @@ package com.alibaba.csp.sentinel.slots.block.authority;
 
 import com.alibaba.csp.sentinel.slots.block.BlockException;
 
-/***
+/**
+ * Block exception for request origin access (authority) control.
  *
  * @author youji.zj
+ * @author Eric Zhao
  */
 public class AuthorityException extends BlockException {
 
@@ -27,6 +29,10 @@ public class AuthorityException extends BlockException {
         super(ruleLimitApp);
     }
 
+    public AuthorityException(String ruleLimitApp, AuthorityRule rule) {
+        super(ruleLimitApp, rule);
+    }
+
     public AuthorityException(String message, Throwable cause) {
         super(message, cause);
     }
@@ -40,4 +46,15 @@ public class AuthorityException extends BlockException {
         return this;
     }
 
+    /**
+     * Get triggered rule.
+     * Note: the rule result is a reference to rule map and SHOULD NOT be modified.
+     *
+     * @return triggered rule
+     * @since 1.4.2
+     */
+    @Override
+    public AuthorityRule getRule() {
+        return rule.as(AuthorityRule.class);
+    }
 }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/authority/AuthoritySlot.java

@@ -58,7 +58,7 @@ public class AuthoritySlot extends AbstractLinkedProcessorSlot<DefaultNode> {
 
         for (AuthorityRule rule : rules) {
             if (!AuthorityRuleChecker.passCheck(rule, context)) {
-                throw new AuthorityException(context.getOrigin());
+                throw new AuthorityException(context.getOrigin(), rule);
             }
         }
     }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/degrade/DegradeException.java

@@ -26,6 +26,10 @@ public class DegradeException extends BlockException {
         super(ruleLimitApp);
     }
 
+    public DegradeException(String ruleLimitApp, DegradeRule rule) {
+        super(ruleLimitApp, rule);
+    }
+
     public DegradeException(String message, Throwable cause) {
         super(message, cause);
     }
@@ -38,4 +42,16 @@ public class DegradeException extends BlockException {
     public Throwable fillInStackTrace() {
         return this;
     }
+
+    /**
+     * Get triggered rule.
+     * Note: the rule result is a reference to rule map and SHOULD NOT be modified.
+     *
+     * @return triggered rule
+     * @since 1.4.2
+     */
+    @Override
+    public DegradeRule getRule() {
+        return rule.as(DegradeRule.class);
+    }
 }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/degrade/DegradeRuleManager.java

@@ -76,7 +76,7 @@ public class DegradeRuleManager {
 
         for (DegradeRule rule : rules) {
             if (!rule.passCheck(context, node, count)) {
-                throw new DegradeException(rule.getLimitApp());
+                throw new DegradeException(rule.getLimitApp(), rule);
             }
         }
     }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowException.java

@@ -23,10 +23,13 @@ import com.alibaba.csp.sentinel.slots.block.BlockException;
 public class FlowException extends BlockException {
 
     public FlowException(String ruleLimitApp) {
-
         super(ruleLimitApp);
     }
 
+    public FlowException(String ruleLimitApp, FlowRule rule) {
+        super(ruleLimitApp, rule);
+    }
+
     public FlowException(String message, Throwable cause) {
         super(message, cause);
     }
@@ -40,4 +43,15 @@ public class FlowException extends BlockException {
         return this;
     }
 
+    /**
+     * Get triggered rule.
+     * Note: the rule result is a reference to rule map and SHOULD NOT be modified.
+     *
+     * @return triggered rule
+     * @since 1.4.2
+     */
+    @Override
+    public FlowRule getRule() {
+        return rule.as(FlowRule.class);
+    }
 }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowSlot.java

@@ -151,7 +151,7 @@ public class FlowSlot extends AbstractLinkedProcessorSlot<DefaultNode> {
         if (rules != null) {
             for (FlowRule rule : rules) {
                 if (!canPassCheck(rule, context, node, count, prioritized)) {
-                    throw new FlowException(rule.getLimitApp());
+                    throw new FlowException(rule.getLimitApp(), rule);
                 }
             }
         }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/system/SystemBlockException.java

@@ -22,25 +22,34 @@ import com.alibaba.csp.sentinel.slots.block.BlockException;
  */
 public class SystemBlockException extends BlockException {
 
-    String resourceName;
-
-    public String getResourceName() {
-        return resourceName;
-    }
+    private final String resourceName;
 
     public SystemBlockException(String resourceName, String message, Throwable cause) {
         super(message, cause);
         this.resourceName = resourceName;
     }
 
-    public SystemBlockException(String resourceName, String ruleLimitApp) {
-        super(ruleLimitApp);
+    public SystemBlockException(String resourceName, String limitType) {
+        super(limitType);
         this.resourceName = resourceName;
     }
 
+    public String getResourceName() {
+        return resourceName;
+    }
+
     @Override
     public Throwable fillInStackTrace() {
         return this;
     }
 
+    /**
+     * Return the limit type of system rule.
+     *
+     * @return the limit type
+     * @since 1.4.2
+     */
+    public String getLimitType() {
+        return getRuleLimitApp();
+    }
 }

sentinel-extension/sentinel-parameter-flow-control/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/param/ParamFlowException.java

@@ -32,11 +32,17 @@ public class ParamFlowException extends BlockException {
         this.resourceName = resourceName;
     }
 
-    public ParamFlowException(String resourceName, String message) {
-        super(message, message);
+    public ParamFlowException(String resourceName, String param) {
+        super(param, param);
         this.resourceName = resourceName;
     }
 
+    public ParamFlowException(String resourceName, String param, ParamFlowRule rule) {
+        super(param, param);
+        this.resourceName = resourceName;
+        this.rule = rule;
+    }
+
     public String getResourceName() {
         return resourceName;
     }
@@ -45,4 +51,26 @@ public class ParamFlowException extends BlockException {
     public Throwable fillInStackTrace() {
         return this;
     }
+
+    /**
+     * Get the parameter value that triggered the parameter flow control.
+     *
+     * @return the parameter value
+     * @since 1.4.2
+     */
+    public String getLimitParam() {
+        return getMessage();
+    }
+
+    /**
+     * Get triggered rule.
+     * Note: the rule result is a reference to rule map and SHOULD NOT be modified.
+     *
+     * @return triggered rule
+     * @since 1.4.2
+     */
+    @Override
+    public ParamFlowRule getRule() {
+        return rule.as(ParamFlowRule.class);
+    }
 }

sentinel-extension/sentinel-parameter-flow-control/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/param/ParamFlowSlot.java

@@ -81,12 +81,12 @@ public class ParamFlowSlot extends AbstractLinkedProcessorSlot<DefaultNode> {
                     // Here we add the block count.
                     addBlockCount(resourceWrapper, count, args);
 
-                    String message = "";
+                    String triggeredParam = "";
                     if (args.length > rule.getParamIdx()) {
                         Object value = args[rule.getParamIdx()];
-                        message = String.valueOf(value);
+                        triggeredParam = String.valueOf(value);
                     }
-                    throw new ParamFlowException(resourceWrapper.getName(), message);
+                    throw new ParamFlowException(resourceWrapper.getName(), triggeredParam, rule);
                 }
             }
         }